There is a semiconductor device such as a power metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) in which a gate electrode and a gate insulating film are formed on an inner wall of a trench formed in a front surface of a semiconductor substrate.
A semiconductor device is disclosed in US 2016/0043000 in which a trench buried with a gate electrode of an MOS diode is formed between trenches buried respectively with gate electrodes of two MOSFETs adjacent to each other and formed in a semiconductor substrate.